C-Nuclear Magnetic Resonance NMR

Although it is required to refine the above condition I in actuality, this rather simple but impressive prediction seems to have much stimulated the experiments on the electrical-conductivity measurement and the related solid-state properties in spite of technological difficulties in purification of the CNT sample and in direct measurement of its electrical conductivity (see Chap. 10). For instance, for MWCNT, a direct conductivity measurement has proved the existence of metallic sample [7]. The electron spin resonance (ESR) (see Chap. 8) [8] and the C nuclear magnetic resonance (NMR) [9] measurements have also proved that MWCNT can show metallic property based on the Pauli susceptibility and Korringa-like relation, respectively. On the other hand, existence of semiconductive MWCNT sample has also been shown by the ESR measurement [ 10], For SWCNT, a combination of direct electrical conductivity and the ESR measurements has confirmed the metallic property of the sample employed therein [11]. More recently, bandgap values of several SWCNT... 

These derivatives are soluble in an acetone/water mixture with their p i values similar to that of PIDAA. The phenylene analogs are similar to EDTA except that the two nitrogens are bridged by aromatic rings. These derivatives are soluble in acetone/water. They were characterized by measuring their H- and C-nuclear magnetic resonance (NMR) spectra and Fourier transform infrared (FTTR) spectra. All the PIDAA derivatives showed a peak near 53 ppm for the methylene carbons in carbon NMR spectra. The methylene carbon resonance appears around 44 ppm in the NPG derivative. Thus offers an easier way to characterize these materials. The FTNMR data are listed in Table 1 below. 

Interest in the structures and properties of fullerenes has received new impetus from the recent discovery that the molecules Cm and C70 can be prepared in large quantities by comparatively simple procedures. The ready availability of solid samples of Cm and C70 now permits their characterization by a variety of physical methods. In this paper, we report the results of solid-state C nuclear magnetic resonance (NMR) measurements on powder samples of Cm and of a mixture of Cm and C70. Our NMR results indicate that Cm rotates rapidly and nearly isotropically in the solid state at 296 K and that C70 also rotates at 296 K, although somewhat anisotropically. The rotation of Cm molecules becomes slow on the time scale of our measurements at about 100 K. 

Fluorophosphines are tervalent phosphorus compounds containing phosphorus-fluorine bonds and they often show markedly different chemical behavior compared with other halogenophosphines. This article is mainly concerned with recent advances in the chemistry of derivatives of PF 3 of the type PF3 X , with particular reference to (a) synthesis of new structural types, (6) the role of fluorophosphines as ligands, particularly in transition metal complexes, and (c) nuclear magnetic resonance (NMR) studies. 

Proton magnetic resonance spectroscopy and C nuclear magnetic resonance (NMR) spectroscopy have been reported to study the nature of water in hiunan SC (Foreman, 1976 Yamamura and Tezuka, 1989 Jokura et al., 1995). The H-NMR data are useful to study dynamic structural disorder of the intercellular lamellar Upid structure in the SC (Bezema etal., 1996). For further information on the use of NMR for investigating SC stmcture, refer to the review by Abraham et al. (1997). 

The chemical structure of pergolide mesylate was determined from the data of synthetic method, elemental analysis, ultraviolet (UV) spectra, infrared (IR) absorption spectra, hydrogen ( H) and carbon ( C) nuclear magnetic resonance (NMR) spectra, and mass spectra. The following is a summary discussion of the spectroscopic data and potential isomerism of pergolide mesylate to support the confirmation of structure of this compound. ... 

Proton and C nuclear magnetic resonance (NMR) analyses of a variety of 1,4-diazocine derivative have been reported, in the context of both detailed conformational analysis and assessment of potential aromaticity as well as routine structural characterization. Fully unsaturated 1,4-diazocines appear to be represented only as their dibenzo[A/] and dibenzo[e, ] derivatives. A variety of NMR analyses have confirmed or demonstrated the nonplanarity of the diazocine ring in (12 X = NMe,... 

Yoshimoto, K., Y. Itatani, and Y. Tsuda C-Nuclear Magnetic Resonance (NMR) Spectra of O-Acylglucoses. Additivity of Shift Parameters and its Application to Structure Elucidation. Chem. Pharm. Bull. (Japan) 28, 2065 (1980). 

Carboxyl group content is determined either by potentiometric titration of humic material or by calcium acetate titration. Calcium acetate method overestimates carboxyl content by at least 10%. Potentiometric titration of humic substances (pH 2.8) in 0.1 mol 1 KCl with a base up to pH 10 yields more precise values for carboxyl content. C nuclear magnetic resonance (NMR) (solid and liquid) can also be used for carboxyl determination. The results obtained are comparable to potentiometric titration. 

---